Magnet



vdr

Patented May 3, 1927.

UNIES y arm PAUL MACGAHAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR "10 I/VESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATIN OF PENNSYLVANIA.

MAGNET. i

Application led January 8, 1924. Serial No'. 684,977.

My invention relates to magnets and particularly to electrical-measuring instrument magnets that are responsive to temperature changes.

One object of my invention is: to provide a. magnet structure that shall inherently respond to temperature changes to vary the eiect of the magnet'in accordance with temperature conditions.

Another object of my invention is to provide a bimetallic temperature-responsive element in which at least one of the elements 'functions as a magnet.

A further object of my invention is to provide a simple, effective and compact meansfor compensating for the operation of an instrument in accordance with variable thermal conditions.

In practicing my invention, I provide a bimetallic element that is constructed similarly to such elements, as heretofore known, but in which at least one of the metal ele* ments functions as a magnet.

Thus, in electrical measuring instruments and in any other devices, where magnets are employed and where temperature changes vary the efi'ect or function of the magnets, a simple and effective device is provided which compensates for temperature changes.

Figure l of the accompanying. drawings is a diagrammatic view of an indicating elec' i trical measuring instrument employing a bimetallic magnet of my invention, and

Fig. 2 is a similar view of the magnet employed as a damping magnet for the damping disk of an integrating or motor meter of a welleknown type.

Fig. l illustrates an ordinary indicating instrument ot' the moving-coil type, in which a coil l is'mounted to pivot about a core member 2 between pole members 3 that are mounted on a bimetallic magnet structure 4.

In this structure, an inner metal strip 5 is the permanent magnet and an outer metal strip 6, intimately secured to the strip `5, by brazing, welding, riveting, rolling or other suitable method as in a usual bimeta-llic element, is of a material having a greater linear coefficient of thermal expansion than the strip 5. The strip 6 may or may not be of magnetic material, as desired.

IVith the above structure, increase of temperat-ure will cause the air gap between thepole members 3, or between the pole members 3 and the coill, to decrease, thus changintensity in accordance with temperature changes. i l

In FigQ, the magnet structure t is showny in the usual damping-magnet Irelation to a disk 7 mounted on a shaft 8 of a watt-hour meter or other instrument, not shown.

While I have shown and described particular forms of my invention, changes may be edected therein without departing from the spirit and scope thereof, as set forth in the appended claims.

I claim as my invention:

1. In combination, two elements disposed in side-by-side relation and having dii'erent thermal coefficients of expansion for eecting lateral movement thereof' in response to temperature changes, one of said elementsbeing a magnet element having adjacent poles which are moved relatively by Such movement.

2. A magnet structure having adjacent pole portions and a substantially rigid composite body portion joinig the pole portions including a magnetizable element and an element of such thermal coeilicient of expansion as to move the pole portions relative to each other in response to temperature changes. f

3. A magnet structure having adjacent pole portions anda composite body portion extending between the pole portions inc1ud ing side-by-side related elements extending in the direction of the body between said pole portions, one of said elements being magnetizable and another of such thermal coeiiicient of expansion as to bend said body portion laterally of said direction to vary the flux between the pole portions in response to temperature changes.

4. A magnet structure comprising a single homogeneous magnetizable element of substuntially .C-shape and an element of dillerent thermal coefloent of expansion rigidly secured thereto to expand and contract the nmgnetzahle element tol thereby move the ends of the magnetzable `element relative to each other.

5. A magnet structure comprising a single homogeneous magnetzable element of substantnlly C-shape and an element of slmhu:

shape und of different thermal coeflleent of expansion rigidly secured in side-by-side relation thereto to move the ends ol*I the magnetiznble element relativo to each other ln response to temperature changes.

In testimony whereof, I have hereunto sul)- scribed my name this 27th day of December,

PAUL MACGAI'IAN. 

